Li Yong, Wang Rong, Chen Hui-Qing, Wei Ruo-Fan, Liu Kun, Ding Wan-Long
Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College Beijing 100193, China.
Zhongguo Zhong Yao Za Zhi. 2021 Jun;46(11):2783-2787. doi: 10.19540/j.cnki.cjcmm.20210227.102.
Root rot was occurred widely in the production area of Rehmannia glutinosa, and which result in serious influence on the yield and quality of R. glutinosa. In the present work, a new phytopathogen was isolated from roots with root rot symptom in the production area of R. glutinosa. The colony of the pathogen growing on PDA medium was gray-black, the structure of hyphae was compact, the aerial hyphae was less developed, and the back of the colony was black. The hyphae of the pathogen were uneven in size, about 2 to 3 μm in diameter and twined with each other, the conidia of the pathogen were small, nearly round and about 1 μm in diameter. The healthy roots of R. glutinosa were inoculated with the pathogen in vitro, black-brown rot was observed at the inoculate sites after a few days' incubation. The rhizosphere soil of healthy R. glutinosa seedlings were inoculated in vivo, the leaves were wilted and the roots were black-brown rotted after several days' normal culture, the symptoms were consistent with those observed in the field. The genomic DNA of the pathogen was amplified by fungus rDNA-ITS universal primer ITS1/ITS4 and homologous analyzed, the pathogen was in a branch with Heterophoma sp., Phoma sp., P. novae-verbascicola and P. herbarum with the nuclear acid homology of 99.21% to 99.43%. The pathogen shown 97.00% to 98.02% nuclear acid homology with H. verbascicola, H. novae-verbascicola, H. poolensis, P. herbarum, H. sylvatica, H. verbascicola and H. verbasci-densiflori when amplified by the tub2 gene special primer Btub2 fd/Btub4 rd, and H. novae-verbascicola was the highest. The pathogen was in a branch with H. novae-verbascicola when amplified by the lsu gene special primer LR0 R/LR7. Based on the morphological characteristics, nucleotide sequence analysis and Koch's test results, the isolated pathogen causing root rot of R. glutinosa was identified as H. novae-verbascicola. This study is of great significance for the further theoretical research on root rot of R. glutinosa and root rot control in field.
地黄产区根腐病发生普遍，对地黄的产量和品质造成严重影响。在本研究中，从地黄产区有根腐症状的根部分离到一种新的植物病原菌。该病原菌在PDA培养基上生长的菌落为灰黑色，菌丝结构紧密，气生菌丝发育较差，菌落背面为黑色。病原菌的菌丝粗细不均，直径约2至3μm，相互缠绕，分生孢子小，近圆形，直径约1μm。将病原菌接种到地黄健康根上进行离体培养，培养几天后接种部位出现黑褐色腐烂。对地黄健康幼苗根际土壤进行活体接种，正常培养几天后叶片萎蔫，根部黑褐色腐烂，症状与田间观察一致。用真菌rDNA-ITS通用引物ITS1/ITS4扩增病原菌的基因组DNA并进行同源性分析，该病原菌与异形茎点霉属、茎点霉属、新 Verbascicola茎点霉和草本茎点霉在一个分支上，核酸同源性为99.21%至99.43%。用tub2基因特异引物Btub2 fd/Btub4 rd扩增时，该病原菌与 Verbascicola茎点霉、新 Verbascicola茎点霉、Poolensis茎点霉、草本茎点霉、Sylvatica茎点霉、Verbascicola茎点霉和 Verbascidensiflori茎点霉的核酸同源性为97.00%至98.02%，其中与新 Verbascicola茎点霉的同源性最高。用lsu基因特异引物LR0 R/LR7扩增时，该病原菌与新 Verbascicola茎点霉在一个分支上。根据形态特征、核苷酸序列分析和柯赫氏法则试验结果，鉴定分离到的引起地黄根腐病的病原菌为新 Verbascicola茎点霉。本研究对地黄根腐病的进一步理论研究及田间根腐病防治具有重要意义。
